Method and apparatus for sealing containers



Dec. 19, 1950 J. M. SHARF 2,534,305

ms'mon AND APPARATUS FOR SEALING CONTAINERS Filed June 27, 1947 3Sheets-Sheet 1 IN VEN TOR.

Dec. ,1950 J. M. sHARF 2,534,305

METHOD AND APPARATUS FOR SEALING CONTAINERS Filed June 27, 1947 3Sheecs-Sheet 2 INVEN TOR.

J. M. SHARF METHOD AND APPARATUS FOR SEALING CONTAINERS Filed June 27,1947 Dec. 19, 1950 5 Sheets-Sheet 3 INVENTOR.

Patented Dec. 19, 1950 UNITED STATES PATENT OFFICE 2,534,305 v MErHooAND APYARATUS Foe SEALING CONTAINERS John M. Shari, Lancaster Township,'Lanca'ster County, Pa., assignor to ArmstrongCork Compa-ny,Lancasten'Pa, a corporation of Pennsylvania;

11 Claims.

This invention relatesto a method and, apparatus for sealing containers;The invention is particularly concerned witha method andapparatus forvacuum-sealing containers by the directional flow of steam. or other hotvapor within the open mouth o'f a container above the container contentsto displace the airtherein and the positioning of a closure in sealedrelationship with the container, the head space' of which is filled withvaponand thereafter'permitting the vapor to condense, effecting areduction in pressure within the container.

At the present time, food containers are frequently vacuum-sealed bypassing the filled containers through a steam chamber in which ispositioned a closure-applyingmechanism. The steam envelops theentirecont'ainer, and a substantial quantity of the air within thecontainer is replaced bythe steam'prior to'the application of theclosure. Most commonly, the container is moved'progressivel through thesteam chamber,

and the closure is automatically applied'in the chamber as the containermoves therethrough.

In other sealing machines, the container is positioned Within a cowlingor other similar confining means, and steam is injected into the mouthof the container with a cap positioned above the container. The cap isthen thrust down on the container, entrapping the steam therein;

The first-mentioned method of sealing is obj ectionable for a number ofreasons, among which are the following: In moving a series of containersat high speed througha steam chamber, there is a tendency to create airdrafts and also uncontrolled turbulence within the steam chamher, and,as a frequent consequence, the. degree of pressure reduction within thesealed container is not as high as desired. The'contaminated air whichis not'wholly replaced by steam also tends in some instances todeteriorate the packaged product. Another objection, to this system isthe fact that by merely enveloping the whole container in a steamatmosphere, it is difiicult to quickly displace the air within thecontainer above the container contents. This results in contamination ofcertain food products due to the incomplete scavenging of airfrom withinthe container. Since the steam must be diffused throughout the steamchamber in this system, there is alwaysthe dangerof impropervacuumization resulting from the -replacement of air within the headspace in the container with a mixture of contaminated .rairl and steam,resulting from the incomplete'diffusion'of steam within the steamchamberjand producing a poor quality of stea1n air mixture. ,1 w

In the secondsystem, it very difficult to inject steam at relativelyhigh velocity into the open mouth of the container without at the sametimeentraining air with the jet of steam. Entrained'ai'r disposed withinthecontainer has the same deleterious action as air normally' present inthe container and not removed 'during the sealing operation." i p I M Itis an object of' myinvention to provide a method and apparatus forsealing containers in which the containers may be moved at a rapid rateand substantiallycomplete scavenging of the air from the containerseffected prior to the application of the closureaj w a ,v

A further object of my invention isto provide a method and apparatuswhich will permit theconsistent and eilicient attainment of: a desiredfo r controlled degr'ee'of pressure reduction within the containersbeing sealed through the controlled direction of abody'of steam or othergas or vapordirectly into the container. P

Another object of my invention is to provide a "method and apparatus bywhich the stearn will be directedinto the open'mouth of the containerina limited area diametricallyof the openmouth of the container, and airand steam will be moved laterally outof the container untilsubstantially complete scavenging: has been effected.

A still further object of my inv entio n is to provide a, method andapparatus for directing a laminar ribbon of steam into the open mouth ofthe container and for creating a zone of reduced pressure laterally ofthe ribbon to aid in the scavenging of contaminated air from within thecontainer. o v, A still further object of my invention is to providea'methodand apparatus in which 'a downwardly directed ribbon'of steam,willfbe pr vided fo r passage into the open mouth of the container, andan atmosphere of' steam will be rovided, rising into the open head of"a.con tainer closure, said c1os ure passing through the atmosphere of'steamin its travel to sealing position on the container; p

In order that m inyention maybe readily understood, I shall describ ecertain preferred embodiments thereof in which:

ferred method and forming part'of my improved apparatus Figure 6 is adiagrammatic view illustrating a modification of my invention in which apair of eductors is employed for pressure reduction which aids in thescavenging of air and air admixed with steam from within the container.

Referring to Figure 1, the machine is of more or less conventional type,including a table 2 along which containers are progressively conveyed bymeans of a chain belt not shown. Edge guides 3 are provided on oppositesides of the table and serve to position the containers in their courseof travel through the machine. A cap track 4 is provided which receivesa plurality of closures in an inclined position for disposition upon therespective containers as they move through the machine. Aclosure-applying arrangement 5 in the nature of a spring-actuated chainconveyor is provided, the same being disposed adjacent the closure track4. The foregoing equipment is of conventional type commonly employed inthe steam chamber type of sealing equipment.

In place of a steam chamber, however, there is provided a steamdistributor 6 which is shown in Figure 2. The distributor 6 is providedwith a dephlegmator chamber 7 adjacent its inlet end which is effectivefor removing in the conventional manner entrained water from the steamwhich is inletted through an opening 8 in the distributor. If steam ofhigh quality, substantially free of condensation, is supplied, thedephlegmator may be eliminated. The distributor proper is made up ofsheet metal and includes a plenum chamber formed of side Walls 9 and ID,top wall H, and bottom wall !2. The bottom wall is provided with anopening !3 which extends longitudinally thereof, and when thedistributor is in position, as shown in Figure 1, the opening [3 willlie generally parallel to the length of the table 2 so that containersl4 moving over the table 2 between the guides 3 will pass under thedistributor 6 in alignment therewith. The opening i% may be ofsubstantially uniform width throughout a, major portion of the length ofthe opening or may be tapered, as shown in Figure 5. The opening l3preferably flares at the exit end ii of the distributor, as shown inboth Figures 2 and 5. Downwardly directed guards or fins l6 are providedand define the opening I3.

The end wall I! of the distributor is inclined, as shown in Figure 3,and is provided with an opening I8, as shown in Figures 2 and 5.Mounting brackets is are provided for attaching the steam distributor tothe machine.

In carrying out the method of my invention, steam at a pressure of a fewpounds and a temperature of about 212 F. is inletted into thedistributor through the inlet 8. The steam passes through thedephlegmator chamber 1 where it is expanded to slightly aboveatmospheric pressure, and any condensate in the steam is removedtherefrom. The steam of high quality then passes into the plenum chamberand flows therefrom as a downwardly directed laminar ribbon. The issuingribbon of steam flows downwardly a short distance, sufiicient topenetrate within the container to the upper surface of the containercontents. The ribbon is substantially free of turbulence as it issuesfrom the distributor, being of extremely low. pressure and being guidedby the fins l6; such flow is technically termed a laminar flow, orviscous or streamlined flow to contrast it with a jet flow wherein greatturbulence occurs. Referring to Figure 3, containers 14 are filled withfood or other products to the line 29 or thereabouts with iii aheadspace 2! provided thereabove. The downwardly directed ribbon of steam isconfined against lateral movement by the guards or fins 15 so that theribbon of steam is directed downwardly into the containers, as bestillustrated in Figure 6. It will be observed that the width of theopening 13 is less than the width of the open mouth of the container 14so that the ribbon of steam is directed into the central portion 22 ofthe container, and the portions 23 and 24 thereof are free for theunrestricted lateral fiow of air and steam from within the container. Aspreviously mentioned, the opening I3 is preferably of a width which isless than the width of the container mouth throughout substantially allof the length of the opening. As the container moves progressively underthe steam distributor, the ribbon of steam flows into the open mouth ofthe container into the head space 2|; the steam moves downwardly againstthe surface of the container contents, flowing laterally ther eover andpassing upwardly and outwardly in the areas 23 and 24, sweeping with itthe air within the head space of the container. As the forward progressof the container continues, contaminated air and steam will continue tofiow laterally from the areas 23 and 24 of the container; when by thetime the container reaches the end of the steam distributor,substantially all or at least a substantial portion of the air wili havebeen removed and replaced with high quality steam.

As shown in Figure 4, the container It will then move into a positionwhere a closure 25 will be applied by a mechanism generally indicated bythe numeral 26. Such apparatus forms no part of the present invention,the same being illustrated, described, and claimed in the copendingapplications of Paul Gschwend and the present inventor, Serial No.757,530, filed June 27, 1947, entitled Closure-Feeding Devices, nowPatent No. 2,481,508, and Harold H. Borthwick, Serial No. 757,477, filedJune 27, 1947, entitled Closure-Release Mechanism, now Patent No.2,481,495.

The steam passing through the distributor forms an upwardly directedatmosphere through the opening [8 shown in Figure 2. This atmospherefills the open head of the container closure, and since the fins Itdiverge and form a funnel-like path for steam distribution, anatmosphere of steam is disposed above substantially the entire openmouth of the container and fills the area between the container and itsclosure. As the container l4 moves forward, a closure 25 is extractedfrom the track and is positioned upon the container 14, passing throughthe atmosphere of steam and entrapping steam within the container. Thesteam atmosphere also prevents the entrance of contaminating air intothe container as the closure moves from the track onto the container.After closure application, the introduced steam is permitted. tocondense within the container.

In a modification of my invention shown in Figure 5, the opening [3 inthe bottom wall l2 of the distributor instead of being substantiallyuniform in width throughout its length is tapered gradually from theinlet end 21 thereof to the exit end 28 thereof. I have found that thistends to provide a ribbon of steam when supplied at low pressure whichhas a forward motion along the direction of the length of the openingl3. While this forward motion may not be as rapid as'the rate ofmovement of the containers under the steam distributor, it has beenfound that this forward motion aids in the sweeping out of air from,within the container. In this embodiment, as in the other embodimentsshown, theopening I3 is defined by the fins which serve to confine thelateral movement of the steam. The width of the opening I3 is alsopreferably less than the width of the open mouth of the container to besealed throughout substantially the full length of the opening [3 so asto permit unrestricted lateral flow of air and air and steam during themovement of the container under the distributor and thus obtaineifective scavenging of air from within the head space of the container.

In Figure 6, I have shown a modification of my invention in whicheductors 23 and 3d are provided on opposite sides of the steamdistributor 6. These, eductors serve to create zones of reduced pressurelaterally of the opening it and aid in the withdrawal of air and air andsteam from within the container. This reduced pressure may be attainedby means of water injection nozzles 3i and 32 positioned within theeductors for rapidly condensing steam passing into the eductors. Drainlines 33 and 3d are provided in the eductors. Also shown in Figure 6 areextensions 35 on the fins it which project into the plenum chamber.These extensions serve to prevent any condensate formed in the plenumchamber from dripping along the fins l6 and into the containers movingthereunder. The condensate flows into the dephlegmator chamber 1 fromwhence it is discharged through outlet 36.

While I have mentioned low pressure steam slightly above atmosphericpressure, it will be understood that the pressure will vary, dependingupon the size of the container, the speed of operation of the machine,the depth of he head space, and other variable factors. It should bemaintained as a relatively slowly moving downwardly directed confinedribbon, advancing in laminar flow, so as to avoid the entrainment ofexcessive quantities of air into the container. While it is preferred tohave the ribbon of a width less than the width of the container mouththroughout a major portion, at least, of the length of the ribbon inorder to permit lateral scavenging of contaminated air from within thecon tainer, the ribbon may be of greater width, particularly where theopening tapers in width so as to create the forward motion of the steamheretofore referred to, this action being effective for scavenging thecontaminated air in a direc tion along the length of the ribbon.v Bestresults areachieved, however, where the ribbon is of less width than thecontainer mouth for a sufficient portion of its length to permit lateralscavenging to remove substantially all of the contaminated air.

'The'p'referredtreating medium is steam maintained at a temperature ofabout 212 F., since steam is generally available in large quantities andat low cost in modern food packaging plants. Other heated gases orvapors or mixtures may be employed, however; and if desired, the steamor other vapor may be heated above 212 F. It is well known that thedegree of pressure reduction attainable when the head space of acontainer is filled with steam or the like depends upon the quality ofthe steam and to a lesser extent also upon the temperature of the steam.I prefer to employ a hot condensable vapor or a mixture in which suchvapor is present in a substantial amount. Inert gases of combustion maybe employed in some instances, particularly where a high degree ofpressure reduction is either unessential or undesirable. Such gasesusually contain in excess of 10% of condensable vapor. By superheatingsteam above 212 improved results may be achieved, where a high degree ofpressure reduction is particularly desired.

Condensation of the steam in the container may be hastened by theapplication of jets of cooling water to the container after sealing.This is particularly desirable where the contents are packed hot.

While I have shown in Figure 4 a side-seal press-on type of closure, themethod and appa ratus of this invention are not limited to the use ofthis type of closure. Other types may be employed with equally goodresults.

While I have illustrated and described certain preferred embodiments ofmy invention, it may be understood that the same may be otherwiseembodied and practiced within the scope of the following claims.

I claim:

1. In a method of vacuumizing containers, the steps comprising directinga single ribbon of, low velocity steam advancing in flow approachingideal laminar flow downwardly into the open mouth of a container movingalong the length of said ribbon, said ribbon being directed into thecontainer along a narrow path passing through the center of thecontainer mouth, confining the lateral movement of said single ribbon ofsteam as it enters the container mouth but permitting unrestrictedlateral flow within the container and outwardly from the ribbon oneither side thereof until substantially all of the air has beenscavenged from within the container, and thereafter sealing thecontainer, entrapping steam therein.

2. In a method of vacuumizing containers, the steps comprisingestablishing a downwardly directed ribbon of low velocity steamadvancing in flow approaching ideal laminar flow, progressively moving acontainer to be vacuum-sealed along the length of said ribbon with thesteam displacing a substantial quantity of the airwithin the containerduring its progressive movement along the length of said ribbon,simultaneously creating a zone of reduced pressure laterally of theribbon of steam to withdraw scavenged air laden steam displaced by steamwithin the container, and applying a closure to the container,entrapping steam therein.

3. In a method of vacuumizing containers, the steps comprising directinga ribbon of low velocity steam advancing in flow approaching ideallaminar flow downwardly into the open mouth of a container moving alongthe length of said ribbon, confining the lateral movement of the steamas it enters the mouth of the container to a portion only of the openingin the ,container and simultaneously withdrawing air and con-.

taminated steam from within the container until a substantial portion ofthe air has been removed from the container, establishing an atmosphereof steam contiguous with one end of said ribbon, and moving a closurethrough said atmosphere and onto the open mouth of a container leavinsaid ribbon, entrapping steam within the open head of the closure duringsealing of the container.

4. In a method of sealing containers under vacuum, the steps comprisingestablishing a ribbon of low velocity steam advancing in flowapproaching ideal laminar flow and moving downwardly and having aforward component of movement in a direction along the length of saidribbon, progressively moving a container to be sealed along the lengthof said ribbon in the direction of longitudinal flow of steam wherebythe steam and container advance together until the steam has displaced asubstantial quantity of the air within the container, and applying aclosure to the container, entrapping steam therein.

5. In a vacuum-closing machine, a steam distributor comprising a steamchamber having a slot in the bottom thereof for directing a laminarflowing ribbon of steam into the open mouth of a container movingtherebelow, and eductors comprising means for creating zones of reducedpressure positioned on opposite sides of said slot for withdrawing airand steam from the container mouth laterally of the zone of steamejection into the container to effect a scavenging of air within thecontainer and its replacement by steam by the combined action of theevolvent ribbon of steam and the eductors.

6. In a vacuum-closing machine, a steam distributor comprising a steamchamber having a slot in the bottom thereof for directing a laminarflowing ribbon of steam into the open mouth of a container movingtherebelow, downwardly directed fins defining the opening in saidchamber, and eductors positioned laterally of said fins and comprisingmeans for creating zones of reduced pressure laterally of the zone ofsteam evolvement.

7. In a vacuum-closing machine in which hot condensable vapor isdirected into the open mouth of a container, a vapordistributorcomprising a plenum chamber having a substantiallyunrestricted, longitudinally directed narrow slot extending throughout asubstantial portion of the length of the bottom wall of the plenumchamber and of a width throughout a major portion at least of its lengthwhich is less than the width of the mouth of a container to bevacuum-sealed for directing a ribbon of vapor advancing in flowapproaching ideal laminar flow into the open mouth of a container movingtherebelow with an area laterally disposed with respect to the zone ofsteam ejection into the container for the Withrawal of air andcontaminated steam from the container mouth, and means for conveyingsaid container progressively below said opening and substantiallyparallel to the length of the said opening.

8. In a vacuum-closing machine in which hot condensable vapor isdirected into the open mouth of a container, a vapor distributorcomprising a plenum chamber having a substantially unrestricted,longitudinally directed narrow slot extending throughout a substantialportion of the length of the bottom wall of the plenum chamber and of awidth throughout a major portion at least of its length which is lessthan the width of the mouth of a container to be vacuum-sealed,

and downwardly directed guards projecting below the bottom wall of saidchamber adjacent both sides of the slot for directing a ribbon of vaporadvancing in flow approaching ideal laminar flow into the mouth of acontainer moving therebelow with areas of the container mouth disposedlaterally of said guards for the withdrawal of air and contaminatedsteam from the container mouth.

9. In a vacuum-closing machine in which hot condensable vapor isdirected into the open mouth of a container, a vapor distributorcomprising a plenum chamber and a vapor inlet into said plenum chamberadjacent the entrance end of said distributor, said chamber having asubstantially unrestricted, longitudinally directed slot extendingthroughout a substantial portion of the length of the bottom of thedistributor and increasing in width from the entrance end to the exitend of the distributor for the delivery of vapor advancing in flowapproaching ideal laminar flow as a ribbon into the mouth of a containermoving therebelow and advancing in similar flow in a direction from theentrance end toward the exit end of the distributor, whereby said ribbonof vapor will move with the container as it travels through the machine.

10. In a vacuum-closing machine in which hot condensable vapor isdirected into the open mouth of a container, a vapor distributorcomprising a plenum chamber having a substantially unrestricted,longitudinally directed narrow slot extending throughout a substantialportion of the length of the bottom wall of the plenum chamber and of awidth throughout a major portion at least of its length which is lessthan the width of the mouth of a container to be Vacuum-sealed fordirecting a ribbon of vapor advancing in flow approaching ideal laminarflow into the open mouth of a container moving therebelow with an arealaterally disposed with respect to the zone of steam ejection into thecontainer for the withdrawal of air and contaminated steam from thecontainer mouth, an inclined end wall in said plenum chamber having anopening therein extending from said slot for establishing a risinatmosphere of vapor from said plenum chamber above said opening, and aclosure track disposed in an inclined position above said end wall withthe lower end thereof which receives a closure for application to acontainer disposed in the path of said atmosphere of steam.

11. In a vacuum-closing machine in which hot condensable vapor isdirected into the open mouth of a container, a vapor distributorcomprising a plenum chamber, a vapor inlet adjacent the entrance end ofsaid plenum chamber, said chamber being of reducing cross-sectional areafrom its entrance end along its length and having a longitudinallydirected narrow slot extending throughout a substantial portion of thelength of the bottom of the distributor and increasing in width from theentrance end to the exit end of the plenum chamber, said slot being of awidth throughout a major portion at least of its length which is lessthan the width of the mouth of a container to be vacuum-sealed, anddownwardly directed guards projecting below the bottom wall of saidchamber adjacent both sides of the slot for directing a ribbon of vaporadvancing in flow approaching ideal laminar flow along the length ofsaid slot, whereby said ribbon of vapor will move with the container asit travels through the machine and areas of the container mouth disposedlaterally oi the guards will permit discharge 9 of air and contaminatedsteam from the container mouth.

JOHN M. SHARF.

REFERENCES CITED The following references are of record in the file ofthis patent:

Number 10 UNITED STATES PATENTS Name Date White Aug. 1, 1933 MinakerJune 9, 1942 Stewart Feb. 23, 1943 Bell Oct, 31, 1944 Rau Oct. 1, 1946Jonas Dec. 23, 1947 Hohl et a1. Apr. 13, 1948

